This a stable release.
https://github.com/anza-xyz/agave/blob/v4.0/CHANGELOG.md
What's Changed
- v4.0: xdp: propagate error from TxLoopBuilder instead of panic on socket creation (backport of #12504) by @mergify[bot] in #12956
- v4.0: blockstore: add secondary feature flag for SIMD-0340 (backport of #12854) by @mergify[bot] in #12949
- Bump version to 4.0.2 by @github-actions[bot] in #12983
Full Changelog: v4.0.1...v4.0.2